The present invention relates to window frame assemblies and, in particular, to an assembly having a sliding panel mechanism and seal system for vehicular backlites. More particularly, the present invention relates to a window frame assembly that has a sliding panel mechanism and seal system for vehicular backlites that is substantially flush mounted into a vehicle body aperture in a vehicle body frame and method for producing.
Pickup trucks and other related vehicles have a rear window, or backlite, that is mounted in the vehicle body aperture, immediately behind the seats in the vehicle passenger compartment. Typically, such backlites are supplied either to the pickup truck manufacturers as body frame assemblies for installation in new vehicles being manufactured on the assembly line, or they may be supplied to retail auto part stores for direct sales to existing truck owners, in the after market.
Backlite assemblies typically include a metal window frame, made of, for example, aluminum, provided with top and bottom channels to facilitate the sliding of the glass panel. Typically, a plastic frame surrounds the entire assembly.
The backlite assembly can then be mounted directly into the vehicle body aperture in the vehicle body frame. This assembly is secured to the vehicle body aperture with adhesives and/or mechanical fastener devices. A urethane adhesive is frequently used in the backlite applications, such adhesive being applied to a mounting surface of either the vehicle body aperture or the backlite assembly prior to the moment at which these two structures are brought into bonding contact. The result of such conventional configurations is that a cumulative thickness of the channel, seals, and various other parts cause the assembly of those parts to typically project outwardly from the vehicle body aperture.
In addition, the backlite assembly in the pickup truck can be a source of problems, such as water leakage. The leakage may occur at an engagement of the backlite assembly and the body panel, which is typically caused by improper adhesive application or body distortion. Water leakage may also occur around a window aperture seal extending about the edges of the window aperture. The edges of the window aperture are formed by fixed panels, which may have a pillar mounted therebetween. Tight sealing is required on all edges of a sliding panel to ensure integrity of the entire window aperture seal.
A primary configuration that has been used in backlite assemblies consists of an assembly having a metal bracket with two channels extending around the complete perimeter of the assembly. The fixed panels are mounted in an outer channel in planar, spaced-apart relationship with two horizontal and two vertical seals secured in the outer channel surrounding the aperture between the panels. The sliding panel is disposed in an inner channel, adjacent the fixed panels. In the closed position, the sliding panel sealably engages the seals to seal the window aperture between the fixed panels and, if necessary, between each other. When moved to an open position, the sliding panel slides in the internal channel to overlap the fixed panels in the outer channel and, if necessary, each other.
The window aperture seals are made from rubber, plastic, or suitable material, for example, ethylene propylene diene monomer (EPDM), and include an extended lip, which flexibly engages the sliding panel to prevent water and dirt from entering around the sliding panel. These seals are mounted in the outer channel between the fixed panels. The window aperture seals facilitate movement of the sliding panel in a horizontal direction while maintaining sufficient pressure at the lip of the seal to prevent water from leaking around the seal to the interior of the assembly and ultimately, into the vehicle passenger compartment.
A manual production step is required to properly install the seals around the window frame assembly. Window manufacturers have found an alternative, but not entirely satisfactory, sealing system, which seals the window frame without discrete rubber or suitable seals, thereby reducing material and labor costs during production operations and improving the integrity of the seal around the sliding panel.
Although rubber or suitable seals are expensive and difficult to install, such may still be required or preferred in certain embodiments. If these seals are not installed properly, then water leakage may occur in the horizontal channels or along the vertical edges of the vehicle body aperture. An improved method, such as encapsulation, for securing these seals about the window frame assembly in the backlite is also desired in the industry.
In addition to the sealing requirements noted above, there are several additional performance requirements, which often present problems in the use of the sliding panel assemblies in pickup trucks. In the closed position, it is intended that the backlite panel assembly maintain the noise level in the passenger compartment within acceptable limits. The noise to be closed out of the vehicle results from wind and road noise. Channel drain holes and other design features are used to remove moisture as it is encountered, but may result in increased noise in the vehicle passenger compartment.
High or variable sliding force is another concern in backlite panel assemblies. The sliding panel typically includes rubber or plastic guides to secure the slidable panel within the bottom internal channel. The slidable panel should slide freely within the guides while still being positioned to sealably engage the lip of the rubber-sealing member. If the seals are installed improperly, due to, for example, misalignment, then the movable panel may be difficult to slide. The channels of the window frame may also be misaligned. The sliding characteristics of the rubber or suitable seals and the channel guides should permit the sliding of the sliding panel while maintaining the necessary seal force between the sliding panel and the seal.
Another problem, which frequently occurs with backlite assemblies, is a sliding panel rattle. When the sliding panel is moved to an open position, the channel guides should retain the sliding panel, so as to prevent rattling of the panel, during operation of the vehicle.
Achieving a substantially flush window assembly in the vehicle is an additional criterion that has been applied to a sliding panel assembly. The advantage of achieving substantially flush mounting of the sliding panel assembly is that the appearance of the assembly in the vehicle is improved, when compared to sliding panel assemblies that protrude out and away from the vehicle passenger compartment's overall rear body frame.
Typically, substantial flush mounting of the sliding panel assembly can be achieved by: (1) having the panels of the window assembly substantially in the same plane as the window assembly frame, (2) having the sliding panel flush with the fixed panels when the sliding panel is closed and then allowing the sliding panels to be moved behind the fixed panels when the sliding glass is opened, (3) insetting into the vehicle body frame the entire window frame assembly and then bringing the outside surface of the window panels to a substantially flush position in relationship to the vehicle body frame, (4) moving the sliding panels into a recess of the vehicle body aperture, and (5) placing the window assembly in the plane of the exterior vehicle body frame plane and then minimizing the separation of the fixed and sliding panels so as to achieve a substantially flush mounted appearance.
In summary, a backlite window assembly with a sliding panel assembly should maintain a proper seal to reduce or eliminate water leaks and wind/road noise in a closed position. The slidable panel, without compromising the required seal, should be easy to move. In the open position, the sliding panel assembly should be secured in the channel to prevent rattling of the panel. For appearance, substantially flush mounting is a desirable feature that can be applied to a backlite window assembly.
Adhesives are used, conventionally, to secure the backlite assembly in the body opening of a pickup truck and to secure the rubber or suitable seals and the guides in the assembly. Slip coats and other lubricants are often used to facilitate the sliding of the sliding panel assembly against the window aperture seal and the guide walls. Applying adhesives and lubricants in such proximity on the same assembly line adds to the production costs and could cause quality problems if either is applied improperly.
A window frame assembly for pickup truck backlites is disclosed in U.S. Pat. No. 5,294,168 to Kronbetter. The Kronbetter window assembly includes a complex top and bottom rail with two channels, an outer channel for mounting the two outer pieces of fixed glass and the rubber or equivalent sealing members, and an inner channel for securing the guides and the sliding windows.
In Kronbetter, the assembly of the window frame starts with the insertion of the guides into the inner channels. Adhesive is applied to the outer channel to secure the fixed window panels in the window frame. The sliding window panels are inserted into the guides and the bottom metal window frame segment and the bowed, top metal window frame segment are welded or otherwise bonded together. The sealing members are then placed in the outer channel of the window frame to slidably and sealably engage the sliding panels in the inner channel. The window frame assembly is then ready for installation into a pickup truck.
The metal window frame of the window assembly in Kronbetter is expensive to manufacture and assemble. Pickup truck manufacturers, for example, currently, desire a less expensive window assembly that is easier to mount and still meets all of the performance requirements.
In recent years, motor vehicle glass suppliers have been supplying to motor vehicle manufacturers, modular windows having urethane gaskets molded in situ by means of reaction injection molding (RIM). These gaskets encapsulate the peripheral edge of the glass window and provide an effective seal between the glass and the vehicle body frame in the vehicle body aperture. Encapsulation of a gasket is accomplished by placing a glass sheet in a suitable mold and then injecting into the mold a plastic-forming composition, which is in a liquid form, about the window frame periphery thereof, wherein the composition polymerizes and cures in contact with the sheet and tightly adheres thereto.
Prior to the development of the reaction injection molding process, vehicle window assemblies were comprised of a plurality of elements, including adhesive sealants applied around the marginal edges of the panel sheet, suitable mechanical fasteners such as metal clips, and exterior decorative trim strips disposed to cover the junction between the marginal edges of the panel sheet and the adjacent portion of the vehicle body frame.
The initial vehicular window gaskets were formed from a molded plastic material, such as polyvinyl chloride. The relatively high pressure required for the PVC injection molding process, however, resulted in glass breakage and other production related problems. The PVC window assembly process is described, for example, in U.S. Pat. No. 4,072,340 to Morgan.
In the 1980's, the reaction injection molding encapsulation process was developed to produce modular windows, which would reduce glass breakage and facilitate the installation of motor vehicle windows by robots. U.S. Pat. No. 4,561,625 to Weaver describes the use of polyurethanes molded on the peripheral edges of the glass at low pressures through the use of a RIM technique. The polyurethane gasket was of great significance since it eliminated the need for the conventional adhesive sealants, ancillary metal clips and exterior decorative trim strips disposed to cover the junction between the marginal edges of the glass sheet and the adjacent portions of the vehicle body frame.
More recently, injection molding processes, using PVC to form an encapsulated frame seal, have been applied with favorable results, since the PVC materials are, typically, less expensive than the materials used in RIM processes.
U.S. Pat. No. 4,755,339 to Reilly et al. and U.S. Pat. No. 4,839,122 to Weaver disclose further details regarding the method and apparatus for reaction injection molding of window gaskets.
Metal brackets and spacers have been incorporated into the reaction injection molding process to improve the functionality of the glass. U.S. Pat. No. 4,662,113 to Weaver shows a window assembly used for door windows on motor vehicles, which is operated in a vertical manner. A bracket is placed in the mold with the window glass and is integrally secured to the window glass during the formation of the gasket by the RIM injection molding process. The bracket provides a means to connect a linkage or other drive means to the window glass to raise and lower the window in the motor vehicle.
U.S. Pat. No. 4,951,927 to Johnston et al. shows a spacer element used to maintain spacing between two sheets of glass. The spacer is positioned about the window frame periphery of the sheets of glazed glass prior to positioning the glass in a mold for reaction injection molding, in order to form an encapsulating gasket around the peripheral edge portions of both sheets of glass, so as to produce a multiple glazed structure.
Because of the desirable features of the gaskets formed by reaction injection molding, the process has been used for several additional applications. U.S. Pat. No. 5,060,440 to Weaver discloses two glass sheets flexibly connected by adjacent gaskets joined during the reaction injection molding process. U.S. Pat. No. 4,996,808 to Weaver discloses an encapsulated window assembly in which a preformed sheet of plastic material is placed in the mold prior to the gasket forming process.
More recently, seal encapsulation techniques have been proposed, where thermoplastic elastomers are applied. U.S. Pat. No. 5,822,932 to Agrawal discusses the improved long-term, failure-resistant bonding that gaskets made from melt-processible thermoplastics provide over typical RIM materials.
U.S. Pat. No. 6,293,609 to Xu et al. is cited, wherein the potential benefits of thermoplastic elastomers over typical RIM urethane and PVC material are discussed. Some of those benefits are: (1) improvement in seal life when the seal experiences prolonged exposure to UV light, (2) lower manufacturing cycle time to produce the seals, (3) lower material costs, (4) longer seal life due to more resistance to tension or shear forces between the seal and the window panel, (5) less complex seal manufacturing, where added gaskets and sealants are not required, (6) better low temperature operating characteristics, and (7) better “creep” resistance, where “creep” is the movement of a seal from its intended sealing position.
Regarding substantially flush mounting of sliding window assemblies, U.S. Pat. No. 5,442,880 to Gipson achieves substantially flush mounting by placing the outside surfaces of the panels in substantially the same plane as the sliding window assembly's peripheral frame. In the Gipson patent, the outside surface of the panels and the outside surface of the peripheral frame, however, appear to protrude from the outside surface of the vehicle frame surface.
U.S. Pat. No. 5,522,191 to Wenner et al. achieves the appearance of substantially flush mounting by allowing the sliding window assembly to protrude into the vehicle passenger compartment while displacing the exterior surface of the slider window assembly essentially in-line with the contour of the adjacent body panel.
U.S. Pat. No. 5,542,214 to Buening uses a mechanism to place the sliding glass in the same plane as the fixed glass plane when the sliding glass is in the closed position, wherein the sliding glass pane is moved in-line with the fixed panes. To open the sliding glass pane, a grooved slide is provided for the mechanism to place the sliding glass inside of the vehicle passenger compartment and behind the fixed glass panes.
U.S. Pat. No. 5,799,444 to Freimark et al. has a sliding vehicle window that is substantially flush with the fixed glass panes when the window aperture is closed. Through the use of a cam mechanism, the sliding glass pane is placed inside the vehicle passenger compartment, which allows the sliding glass pane to move away from the window aperture and then behind the fixed glass panel.
U.S. Pat. No. 6,220,650 to Davis et al. provides a substantially flush mounted, sliding glass panel that can be used as a vent window on the side of a vehicle or as a backlite in a rear window, wherein the slidable window moves down in a door panel or in a rear recess panel, much like a conventional vehicle side window.
Still, those skilled in the art continued to seek a solution to the problem of how to provide a better substantially flush mounted vehicular window frame assembly.